There's also a burgeoning community of hobbyists building their own 3D printers based on open source designs, such as RepRap, and sharing designs for a wealth of objects through the online portal Thingiverse.

Even more exotic uses of 3D printers are being researched, including machines that build bone using stem cells and that create objects out of wood filaments, cement polymer and salt.

"3D printing is really reaching out and touching everything. It's comparable to the web in that it's a technology that can be applied to whatever you want it for," said Dave Marks, media and content director for 3D Printshow, which provided the printers for the show.

The breadth of what 3D printers can build was on show at the Science Museum in London, which yesterday opened an exhibit of more than 600 3D printed objects ranging from satellite sensors to prosthetic arms.

3D printing has several advantages over traditional manufacturing techniques. Building a model doesn't require spending thousands or more to set up machine tools and then thousands more when you want to change that model. It makes it financially viable to build one-off models and to tweak and customise 3D models in a way that would rapidly become hugely expensive using traditional manufacturing methods. Making simple repairs to old household appliances, rather than replacing them, also becomes more viable when spare parts can be printed off in your living room, rather than having to be tracked down and ordered online. Using a 3D printer also cuts down the supply chain: the network of factories, warehouses and shipping companies normally needed to get a product to an end user.

3D printing can also build objects using novel materials with complex shapes and structures that would be extremely difficult to reproduce using traditional methods. General Electric recently revealed a 3D-printed ceramic and carbon fiber jet engine whose lightweight design should allow for fuel economy unmatched by conventionally made counterparts. Waste can be reduced as the printer is generally using only the materials needed to build the object, rather than carving material out of a larger structure to create an object.

But in general 3D printers are also slow, two-inch high figurines printed out at the Science Museum exhibition took about one hour to print, are far more expensive than traditional manufacturing techniques for mass production and consumer grade 3D printers are only able to produce relatively simple plastic models.

How 3D printers work

3D printers work by taking a 3D computer model and slicing it into layers. The 3D printer then builds the object layer by layer using one of a number of methods.

Most home and hobbyist printers print using Fused Deposition Modeling (FDM), which basically builds a model out of molten plastic. FDM machines feed plastic thread into a printer head, where the plastic is melted and squeezed out of a nozzle called an extruder. The head traces the outline of each layer, gradually building the model using melted plastic.

The quality of the finished model depends on many factors, including the quality of the base material, how thinly sliced the model is, the mechanics of the 3D printer and the care taken in preparing the 3D computer model.

Yet the quality of 3D models produced by FDM generally don't match those built by some other more costly 3D printing technologies used by industry. One such technology is laser sintering.

Laser sintering uses a laser to fuse powder together into the model. The process works by tracing the outline of each each layer onto powdered material using a laser to fuse the object together layer by layer. Laser sintering is able to reproduce fine details and build models out of a wider range of materials than FDM, such as ceramics, metals and glass.

While the FDM printers available to novice home users today generally produce relatively simple models in a single colour and material, more advanced machines are becoming available.

The quality of 3D printers available to home users is expected to take a leap forward from next year after patents run out on key technologies related to laser sintering, which in the long run may make sintering machines affordable for the home user.

A bank of 3D printers were on display at the exhibition building models of people scanned at the museum.

Each figurine takes roughly one hour to print, but the time can vary depending on the level of detail reproduced on the finished object.

The level of detail can be adjusted by altering the thickness of the layer of the model printed out, generally the thinner layer the greater the detail and the longer the model will take to print out.

This machine is a first generation Ultimaker 3D printer, a roughly $1,000 FDM machine that prints in one colour, similar to many other machines aimed at the home market.

Common uses of home 3D printers include creating bespoke items such as phone cases and customising toys for children.

While demoing the Ultimaker at the exhibit a model print had to be abandoned after the half-printed model came loose from the base, a problem that originated from how the print job had been set up. 3D printers need to become as simple as 2D printers to set up and use if they are to gain mainstream acceptance, according to 3D Printshow's Masters.

"For a paper printer you shove in a print cartridge and off you go," he said.

"For a 3D printer there is a certain amount of parameter tweaking, a certain amount of skill that is required to get the best quality out of the machine."

3D printed drugs anyone? The feasibility of making pills using a 3D printer is being studied by a research group at the University of Nottingham in England.

Printing pills could allow doctors to tailor the pharmaceutical make-up of each capsule to individual patients, as well as adding additional beneficial properties, for example applying a coating that would delay the release of a drug for a specific period.

3D printers have also been used to create a scaffold for bone to grow to upon when treating hospital patients.

Professor Dietmar Hutmacher from the University of Queensland in Australia used 3D printing to help repair a hole in a nine year old girl's skull.

The professor took a 3D scan of the girl's skull and used it to design a 3D scaffold that could be placed in the missing piece of her skull.

Inside the scaffold was a precise network of channels that could hold bone cells and allow new tissue to grow. The scaffold was printed using biodegradable materials, which meant after three years it dissolved, leaving new healthy bone that filled in the hole in her skull.

This stainless steel car engine part was created using a laser-sintering 3D printer.

While laser sintering printers are currently one of the priciest variety of 3D fabricators available, they also reduce waste as any unused metal powder can be reused.

This satellite sensor was produced by printing electrical circuits using metal inks.

Printing sensors directly into a satellite's structure saves a lot of room, according to the team that made the sensor from the University of Texas.

The technique may one day provide a reliable way to print out electronic gadets, by printing out circuits inside their casing, said Ryan Wicker, mechanical engineering professor at the university.

The sensor is being sent into orbit for testing in the harsh environment of space, where satellites are subjected to extremes of temperature and heavy doses of solar radiation.

One of the more contentious uses of 3D printers is to produce weaponry.

This is a gun that was printed out by a Finnish journalist, who downloaded a design freely available on the internet, printed out the pistol, dubbed the 'Liberator', and fired it.

The bullet fired straight down the range but the gun broke into four pieces.

Debate is currently taking place over how to best regulate people's ability to produce weapons using 3D printers.

After South African carpenter Richard Van As lost his fingers in an accident he decided to create a low-cost prosthetic hand for people without fingers.

Dubbed Robohand, the hand was designed by Richard working with a designer based on the other side of the world in Seattle.

The hand is printed out of PLA plastic resin using a MakerBot machine and combined with cables and screws to make the finished prosthesis. It is designed to be worn on the hand and to grasp its fingers the user folds their wrist. The design for the hand is freely available online, allowing anyone with a 3D printer and a few additional parts to build their own version.

This 3D printed titanium lattice has been designed to protect probes in future missions to Mars.

The protection is designed for probes that are intended to collect samples from the Martian surface and then return to Earth. The lattice crush zones are designed to absorb the impact of the probe upon crash landing on the Earth's surface.